Element mounting means for straight bar knitting machines



Oct. 7, 1958 ZER 2,854,835

G. BIT ELEMENT MOUNTING MEANS FOR STRAIGHT BAR KNITTING MACHINES Filed April 26, 1957 2 Sheets-Sheet 1 "ii/{WA A TTORNE Y ELEMENT NT MEANS KN ING MA Filed April 26, 1957 2 Sheets-Sheet 2 Oct. 7, 1958 G BWZER 2,854,835

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nited States Patent Office ELEMENT MOUNTING MEANS FOR STRAIGHT BAR KNITTING MACHINES Gottlob Bitzer, Lincoln. Park, Pa., assignor to Textile Machine Works, Wyomissing, Pa., a, corporation of Pennsylvania Application April 26, 1957, Serial No. 655,396

8, Claims. (Cl. 6686)- This invention relates to warp knitting machines and more particularly to means for mounting the knitting and yarn feedingelements of such machines in a manner to eliminate relative linear movements of the elements, induced by variations in temperatures which would affect their normal operating; relationships;

In warp knitting and like, machines the bars on which; the knitting and yarn feeding elements: are. mounted, are from seven to fourteen feet in length and, areconstructed of materials that not only must provide sufficient rigidity to maintain. correct operating relationships between the elements but must also be readily machinable for facility of manufacture. In such warp knitting machines particu-- larly of the tricot type, which operate at high speeds, suflicient heat is generated by the operating parts of the machine to cause an increase in the temperature of the bars which is considerably above the normal atmospheric temperature in which the machine is operated. This increase in temperature in the bars for the elements has heretofore caused a linear expansion of the bars and consequently linear movements of the elements which very often resulted in misalignment of the elements and damage thereto. The misalignment of the elements is further aggravated by the fact that the bars for the various elements are connected to their operating mechanisms at different points along the length of the bars which causes a linear movement of one group of elements such as the yarn feeding elements in only one direction while the bars for the other elements such as the needles and sinkers, have linear movements in both directions.

In previous attempts toovercome misalignment of the various elements caused by such linear expansion, the bars for both the knitting and yarn feeding elements-were connected to their operating means at the same ends of the bars and while this alleviated the conditions to some extent by causing linear movements of the elements only in one direction neveretheless the different linear expansion encountered due to the different materials and cross sectional areas of the bars continued as a source of trouble.

It is therefore an object of the invention to provide means to overcome the above, mentioned and other difficulties occurring in high speed warp knitting and like fabricating machines employing long supporting bars for the fabricating and yarn feeding elements.

Another object of the invention is the provision of means in a warp or tricot knitting machine for controlling the linear movements of the knitting and yarn feeding elements induced by an increase in temperature of the machine during operation thereof.

A further object of the invention is to provide supporting members for the knitting and yarn feeding elements. of a warp knitting machine which are constructed of materials having a low coefficient of expansion such as Invar which is an alloy steel having a high percentage of nickel.

A still further object of the invention is to; provide a Patented Oct. 7, 1958 needle bar assembly for high speed warp or tricot knitting machines, the primary parts of the assembly being constructed of a material having a low coeficient of linear expansion, such as nickel alloy steel, and other partsv being constructed of a material such as brass having a higher coefficient of linear expansion than the primary parts. of the assembly, the, combination of parts being such that the parts having the higher linear expansion have no. adverse effect on the parts having the lower linear expansion.

With these and other objects in view which will be.- come apparent from the following detailed description of the illustrative embodiment of the invention shown in the accompanying drawings, the invention resides in the novelelements, features of construction and cooperation of parts, as. hereinafter more particularly pointed out in the claims.

In the drawings:

Figure 1 is a view partly in cross section and partly in elevation taken. transversely through the knitting and yarn feeding; elements; of a warp. or tricot knitting machine and showing mounting means for the knitting and yarn feeding means according to the instant invention;

Fig. 2 is a front elevational view on a reduced scale of the nedle bar assembly as seen from the left of Fig. 1, parts of the assembly being broken away;

Fig. 3 is a cross sectional view on an enlarged scale takenalong the line 33 of Fig; 2; and

Fig. 4 is. a detailed view on an enlarged scale of a portion of bar shown within the rectangle A indicated in dot-and-dashoutline on Fig. 1.

Referring to the drawings and more particularly to Fig, 1-, there isshown the; loop forming and yarn feeding means of a warp. or tricot knitting machine including spring beard needles l0, sinkers 11:, a presser member 12' for closing the beards of the needles and front and rear groups of guide members 15 for feeding yarn to the needles. The front and rear groups of guide members 15 are usually embedded. orcast in narrow metal or plastic holders 16. which are secured by bolts 18: to front and rear bars. 17 supported on arms 2%) which are in turn. secured to ashaft 21 supported for rocking movement in. they framework of the machine (not shown). The sinkers 11 are also embedded or cast in narrow metal holders 22 which are secured by bolts 24 to a bar 25 carried on levers, a portion of one: of the levers being shown at 26. The. presses member 12 is secured by rivets 23 or the like to a bar'27= which is. carried on levers, a portion of one ofwhich is: shown at 30. Needles it) are mounted in a needle bar assembly 31 supported on levers, a portion of meet the levers being shown at 33. The bars 17, 25, 27 and the needle barassembly 3 :1 are from seven to fourteen feet in length. and are operated in awell known manner to knit yarnsinto fabric.

The needle bar assembly 31 shown in detail in Figs. 2, 3 and 4 comprisesa bar 32 extending the full length of; the assembly, a bed portion 35 formed of a plurality of abutting sections 36 which are secured to one face 37- ofthe bar by bolts 40 and a plurality ofindividual bed members 41 which are secured in a groove 42 in the face 37 ofthe bar by bolts 45 (Fig. 3). The ends of thebed members are spaced from each other as indicated at 46: (Figs. 2 and 4) for the purpose hereinafter set forth. The 'bed portion 35 is provided with spaced slots 47 which act as seats for shank portions 50 of the needles 10 and the bed members41 are providedwith apertures 51 which are aligned with the slots and are adapted to receive butt portions 52 of the needles, the slots acting to maintain the needles in spaced parallel relation and the apertures acting to prevent both lengthwise and rotative movements of' the needles in the slots. The needles 10 are retained in theslots 41 and: apertures 51 in. the; bed. portion 35 and bed members, respectively, by a series of narrow clamps 55 which are removably secured to the bar 32 by bolts 56.

In the operation of the machine to knit yarns into fabric the needles are moved upwardly between the sinkers 11 to positions in which the tips of heads of the needles are at the level of the eyes in the guide members and the guide members are then rocked about the axis of the shaft 21 to pass between the needles. The guide members are then shogged lengthwise of the row of needles and again pass back between the needles to wrap the yarns carried by the guide members around the heads of the needles. The needles then continue to move upwardly until the yarns are below the beards thereof and then move downwardly to catch the yarns beneath the beards. Upon continued downward movement of the needles the presser member 12 is moved to engage and close the beards of the needles so that they pass through previously formed loops. As the needles continue to move downwardly, the previously formed loops are cast off the needles and the new yarn caught beneath the beards is pulled through such previously formed loops. It will be obvious that the needles, sinkers and guide elements must be accurately spaced with respect to each other and such accuracy must be maintained to avoid interference between these elements as they are moved to knit the yarns into fabric as above set forth.

During operation of the machine, the heat generated by the operating means for the various bars causes the temperature of the bar for the needles 10 to increase up to twenty degrees above the temperature of the room in which the machine is located and the bars for the sinkers 11 and guide members 15 increase in temperature up to ten degrees above room temperature. This increase in temperature causes a cumulative linear expansion of the needle bars conventionally used, which have a length of fourteen feet and which are constructed of steel, of approximately twenty-one thousandths of an inch. The conventional bars for the sinkers and guide members, which are of the same material and length, have a cumulative expansion of approximately eleven thousandths of an inch. However, as will be noted in Fig. 1, the cross sectional areas of the bars 17 and for the guide members 15 and the sinkers 11, respectively, are much smaller than the cross sectional area of the bar for the needles so that the bars for the guide members and sinkers will attain their operating temperature and expanded length in only a fraction of the time required to bring the bar for the needles to operating temperature and expanded length. This results in a misalignment of the needles with respectto the guide members and sinkers at the time the bars are being raised to operating temperature, which is sufficient to cause interference between these elements and damage thereto.

In order to avoid misalignment of the needles and other elements cooperating therewith during heating of the parts from room to operating temperatures, the bars, in accordance with the instant invention, are constructed of a steel alloy referred to in the trade as Invar which is approximately thirty-six percent nickel and has a co efiicient of linear expansion of only one-seventh that of steel and the other metals that were previously employed in constructing the bars for the various elements. Therefore, with the use of Invar the linear increase in the overall length of the needle bar assembly is only approximately three thousandths of an inch and in the bars for the sinkers and guide bars only approximately one and one-half thousandths of an inch, where these; bars are of the conventional length of one hundred and sixtyeight inches, and any misalignment caused by the increase in temperature is effectively eliminated.

The narrow holders 16 for the guide members 15 and the holders 22 for the sinkers 11 which are secured to the bars 17 and 25, respectively, are usually cast in a metal such as lead or in a plastic material both of which have a. much higher coetlicient of linear expansion than that of the bars on which they are mounted. However, the holders 16 and holders 22 are formed so as to provide sufficient space between each other that the linear expansion of the individual sections will not be transmitted from one to the other. In the needle bar assembly 31, in addition to the bar 32, the sections 36 of the bed portion 35 and the clamps 55 are also made of Invar. Due to the difliculty in drilling the small apertures 51for the butts 52 of the needles 10 in Invar metal, the bed members 41 are constructed of a non-ferrous metal such as brass which also has a coetlicient of linear expansion much higher than that of the Invar portions of the needle bar assembly. The ends of the individual bed member 41 are however, spaced from each other as hereinbefore set forth and the bed members are of such length that the greater linear expansion of these members will not be transmitted to each other nor will it be sufiicient to cause a distortion of the butt ends of the needles and affect the parallel relation of the portions of the needles held in Invar portions of the needle bar assembly.

While the metal Invar is referred to herein, it is to be understood that any metal having the same or similar characteristics may be employed, in constructing the bars for the knitting and yarn feeding elements, that will effectively limit or eliminate the detrimental effects caused by linear expansion in the bars.

Of course, the improvements specifically shown and described by which the above results are obtained, can be changed and modified in various ways without departing from the invention herein disclosed and hereinafter claimed.

I claim:

1. A needle bar assembly for straight knitting machines having a main bar portion, a bed portion secured to said main bar portion and having slots for receiving shank portions of the needles, spaced bed members secured to said main bar portion and having apertures for receiving butts of the needles, and clamps removably carried on said main bar portion for holding the shank portions and butts of the needles in said slots and apertures, respectively, said main bar portion, bed portion and clamps being constructed of an alloy steel having a low coeflicient of linear expansion and said bed members being constructed of a material such as brass having a higher coefficient of linear expansion than said portions of alloy stee 2. A needle bar assembly for straight knitting machines having a main bar portion, a bed portion secured to said main bar portion and having slots for receiving shank portions of the needles, bed members secured to said said main bar portion with the ends thereof spaced from each other and having apertures aligned with the slots in said bed portion for receiving butt portions of the needles, and clamps removably carried on said main bar portion for holding the shank and butt portions of the needles in said slots and apertures, respectively, said main bar portion, bed portion and clamps being constructed of a metal having a low coefficient of linear expansion and said bed member being constructed of a metal having a higher coefficient of linear expansion than that of said main bar portions, bed portion and clamps.

3. A bar assembly for supporting needles for a warp knitting machine having a main bar portion, a bed portion secured to said main bar portion and having slots for receiving shank portions of the needles, bed members secured to said main bar portion with the ends thereof spaced from each other and having apertures aligned with the slots in said bed portion for receiving butt portions of the needles, clamps removably carried on said main bar portion and adapted to hold the shank and butt portions of the needles in said slots and apertures, respectively, said main bar portion, bed portion and clamps being constructed of a steel alloy having a percentage of nickel of the order of thirty-six percent,

and said bed members being constructed of a non-ferrous metal such as brass.

4. A bar assembly for supporting the needles of a warp knitting machine, including a main bar. portion of steel alloy having a percentage of nickel of the order of thirty-six percent, a bed portion of steel alloy having a percentage of nickel of the order of thirty-six percent secured to said main bar portion and having spaced slots for receiving shank portions of the needles, and bed members of brass secured to said main bar portion and having apertures aligned with the slots in said bed portion for receiving butt portions of the needles, said bed members having the ends thereof spaced from each other.

5. A bar assembly for supporting needles for a warp knitting machine, including a main bar portion, a bed portion secured to said main bar portion and having slots for receiving shank portions of the needles, bed members secured to said main bar portion with the ends thereof spaced from each other and having apertures aligned with the slots in said bed portion for receiving butt portions of the needles, and clamps removably carried on said main bar portion for holding the shank and butt portions of the needles in said slots and apertures, respectively, said main bar portion, bed portion and clamps being constructed of a metal having a low coefiicient of linear expansion of the order of nine ten-millionths (0.0000009) of an inch for each degree Fahrenheit of temperature change in the bars between temperature limits of seventy to one hundred degrees Fahrenheit.

6. An elongated bar for supporting knitting elements of a warp knitting machine which is constructed of a steel alloy having a low coeificient of linear expansion of the order of nine ten-millionths (0.0000009) of an inch for each degree Fahrenheit of temperature change in the bar between temperature limits of seventy to one hundred degrees Fahrenheit.

7. An elongated bar for supporting yarn feeding elements of a Warp knitting machine which is constructed of a steel alloy having a low coefii-cient of linear expansion of the order of nine ten-millionths (0.0000009) of an inch for each degree Fahrenheit of temperature change in the bar in a temperature range of seventy to one hundred degrees Fahrenheit.

8. In a warp knitting machine having needles, sinkers and yarn guide members cooperating with each other to form yarns into a knitted fabric, a bar assembly supportiong said needles, a bar supporting said sinkers and a bar supporting said yarn guide members, said supporting bars for said needles, sinkers and yarn guide members being constructed of an alloy steel having a nickel content of the order of thirty-six percent.

References Cited in the file of this patent UNITED STATES PATENTS 2,357,361 Schmidt Sept. 5, 1944 2,366,227 Swicky Jan. 2, 1945 2,709,350 Meyer May 31, 1955 

